The method of these teachings includes processing a semiconductor structure forming an active waveguide of a semiconductor laser in an environment free of contamination in order to provide contamination free mirror facets at the ends of the active waveguide, and depositing a single crystal passivation layer comprised of a semiconductor whose bandgap exceeds that of the active layer and the waveguide layers and that does not form misfit dislocations with the laser diode semiconductor, the deposition occurring at a temperature at which the semiconductor structure does not degrade.